replace one widget with another on a layout with a button

marlenet15

I am trying to replace a qscrollarea with a qgroupbox which contains two qlabels that are images of charts. I have tried the following but nothing happens.

QGroupBox *videoChart = new QGroupBox;
QHBoxLayout *videoChartLayout = new QHBoxLayout;
videoChartLayout->addWidget(leftVideos2);
videoChartLayout->addWidget(rightVideos2);
if(startTest->clicked())
{
    videoChartLayout->removeWidget(instructionsScrollArea1);
    videoChartLayout->addWidget(charts,0,Qt::AlignHCenter);
}
else
{
    videoChartLayout->addWidget(instructionsScrollArea1);
}

videoChartLayout->setStretch(0,2);
videoChartLayout->setStretch(1,2);
videoChartLayout->setStretch(2,6);
videoChart->setLayout(videoChartLayout);

mrjj

Hi
Is that the actual code ?

videoChart = new QGroupBox;

but you add
addWidget(charts,0,Qt::AlignHCenter);

and what is startTest->clicked() ?

marlenet15

@mrjj when I press that button, i would like for the charts to replace the QScrollArea that is there right now. And that is not the whole whole code that it is the section I am trying to say when I click this button replace this with this

mrjj

@marlenet15

Hi. I understand what you want to happen, but code seems
strange. (to me)

the
if(startTest->clicked())

Confused me a bit if startTest is a button. ?

the "clicked" is a signal and should be connected to a slot that will
be called when the buttons is clicked.
calling it directly will not work.

Please place a QPushbutton on the form, then right click it and
select Go to Slot, then select released().
you will then go to a function.
Put you code here.

you can also connect stuff in code:
http://doc.qt.io/qt-5/signalsandslots.html

marlenet15

I have created everything from scratch so nothing is in the ui file. I have tried using SIGNAL and SLOTS but it didn't seem to recognize the widgets I wanted to replace

mrjj

@marlenet15
well in the sample you call the groupbox for videoChart
but in the addwidget you have "charts" ?
I would expect it to be videoChart ?

Well lets assume you replace function is called
ReplaceNow and lives in mainwindow
and your button is called startTest
then you should have to have a statement like

connect( startTest, SIGNAL(clicked()), this, SLOT(ReplaceNow()));

for the button to do anything when clicked.
Not sure if that is your issue ?

marlenet15

@mrjj chart is also a QGroupBox which I didn't include in the code. Sorry. Ok so how will it know what exact widgets to replace? That is my question. Would it be something like this?

void ReplaceNow()
{
 videoChartLayout->removeWidget(instructionsScrollArea1);
 videoChartLayout->addwidget(charts,0,Qt::AlignHCenter);
}

mrjj

@marlenet15
Ahh. ok.
yes then you would use the pointer to the widget.
Like instructionsScrollArea1 if that was the one you used to insert it with in first place?

SGaist

Hi,

Sounds rather like a job for QStackedLayout

marlenet15

@mrjj I did this but it says that the variables are not declared on the scope

void ReplaceNow()
{
 *videoChartLayout->removeWidget(*instructionsScrollArea1);
 *videoChartLayout->addwidget(charts,0,Qt::AlignHCenter);
}

mrjj

@marlenet15

instructionsScrollArea1 and ReplaceNow() should be
in same object or same file at least.

that what scope means.

so where is instructionsScrollArea1 declared and where
is void ReplaceNow() ?

Also
the * in
removeWidget(*instructionsScrollArea1);
is wrong.

If possible,post whole code here and its easier for us to help.